A launchable application is a program that is automatically executed at certain time intervals or under a certain set of conditions. One example of a launchable application is a screensaver. Screensavers originated as a way to prevent an image from burning in to a display monitor. When the same image is left on a monitor for a period of time without the image changing at all, the monitor can be damaged. When the same image is displayed continuously, the phosphorous inside the monitor stays permanently “burned” with the image. This phenomenon is commonly referred to as “burn-in”. Screensavers are designed to constantly show new images on the screen, thereby avoiding burn-in. Screensavers are typically configured to launch automatically when a monitor has been unused for a predetermined period of time.
Though modern monitors are less susceptible to burn-in, screensavers remain popular and have since evolved to serve as a form of entertainment and as an entry point for a system's idle cycles to be used for grid/distributed computing. One example of grid/distributed computing is the Search for Extraterrestrial Intelligence (SETI). SETI is a scientific experiment that uses Internet-connected computers in the search for extraterrestrial intelligence. Users participate by running a program that downloads and analyzes radio telescope data during the computers idle time, (i.e., when a screen saver would be invoked).
Another example of a launchable application is a backup application. It is quite common for computer systems to perform periodic backups of files stored in a data storage system. Backing-up files typically involves transferring a copy of the file stored on the disks within a data storage system to another medium, such as magnetic tape. Backing-up files protects against data loss in the event of disk or data storage system failures. Backup operations are typically performed at set time intervals.